Get in touch with a real estate agent in your area who is experienced and can recommend a lender to you. Often times you will find that local lenders can beat rates of some of the larger banking institution. Speaking with a real estate agent will be your first step. This way, they can advise you on how the home buying process works. You may here that getting pre-approved is the first step, but you should also be advised on what types of questions you should ask your lender before meeting with him/her, etc. Take you time and ask around to friends who own their own home and see who they recommend as well. It's important to research. The lender will tell you about the paper work you will need to bring in order for him/her to get you pre-approved.
The number one thing is to talk to a lender. They will look at your income to debt ratio and will be able to determine what you can afford. My suggestion to buyers is always talk to at least 3 lenders. Lenders are not all the same. It seems as if some can work magic and others are just "doing their job". A simple analogy would be when you are shopping for insurance. Do you only call one company and think that is the best price? No, you call a few to determine who is giving you the best rate. The same goes for lenders. They are all vying for your business. Therefore don't be afraid to let them do some work for you before you choose one. I hope this helps.